Cholecystectomy or gallbladder removal has been carried out in a structured surgical manner since about 1882. The heretofore conventional approach to the procedure has involved the surgical opening of the body cavity, typically via a right quadrant incision, and direct hand access to the organ on the part of the surgeon aided by three-dimensional vision and touch. This surgical procedure continued for over 100 years until the 1980s when a new treatment employing laparoscopy somewhat abruptly supplanted the earlier orthodox procedure. The appeal of this new treatment modality resides in the less invasive character of the procedure, which is carried out with correspondingly less pain, incision, and scar, shorter term hospitalization, and improved cost considerations.
In general, the laparoscopic approach to cholecystectomy commences with the insufflation of the peritoneal cavity of the anesthetized patient. Typically, this expansion of the cavity (pneumoperitoneum) is carried out by the controlled insertion of an insufflating agent such as carbon dioxide through a supraumbilically inserted Verres needle. That needle is operatively associated with an insufflator machine, usually providing a pressure and flow rate control over the insufflating agent. A sequence of cannulas are placed into the peritoneal cavity using sharp, removable inserts called trocars. These cannulas are valved devices through which a video imaging camera and light source along with various thin, elongate instruments can be passed and manipulated from outside of the patient's body during the procedure. Cannulas vary in port diameter, ranging, for instance, from 5 mm to 18 mm. Generally, the first cannula is installed adjacent the umbilicus and serves to initially receive a laparoscope or video camera and light source. It is the video output of this device as observed by the surgeon at a video monitor which provides all of the visual perceptive data for hand maneuvering the elongate laparoscopic instruments. As the video camera is guided by a surgical assistant, these instruments, having a necessary length of about 18 inches (45.72 cm), are held at one end by the surgeon who, while viewing the video monitor, carries out refined and delicate dissecting, isolating and clamping maneuvers within the moving, dynamic environment of the peritoneal cavity.
The gallbladder is the reservoir for bile which, with the hepatic, cystic, and common bile ducts, forms the excretory apparatus of the liver. Conical or pear shaped in gross anatomy, the gallbladder exists as a musculo-membranous sac lodged in a fossa on the undersurface of the right lobe of the liver, and extends from near the right extremity of the transverse fissure to the anterior border of the organ. It is about 4 inches (10.16 cm) in length, 1 inch (2.54 cm) in breadth at its widest part, and holds from eight to ten drachms. The organ is divided into a fundus, body, and neck or infundibulum. The fundus or broad extremity is directed downward, forward and to the right, and projects beyond the anterior border of the liver. The body and neck are directed upward and backward to the left. The vascular system of the gallbladder is derived from branches of the hepatic artery.
The upper surface of the gallbladder is attached to the liver by connective, i.e., areolar, tissue and vessels. The under surface is covered by peritoneum, which is reflected on to it from the surface of the liver. Occasionally, the whole of the organ is invested by the serosa membrane, and is then connected to the liver by a kind of mesentery. Adipose tissue often invests the gallbladder and its biliary and vascular anatomy.
In wall structure, the gallbladder consists of three coats, namely, serous, fibrous and muscular, and mucous. The external or serous coat is derived from the peritoneum and completely invests the fundus, but covers the body and neck only on their under surface. The fibro-muscular coat is a thin but strong layer which forms the framework of the sac and consists of dense, fibrous tissue which interlaces in all directions. The internal or mucous coat is loosely connected with the fibrous layer and is covered with columnar epithelium. The mucous membrane secretes an abundance of thick, viscid mucus.
As aforementioned, both the gallbladder and liver are associated with a biliary anatomy including three biliary ducts: the cystic duct, the common bile-duct (ductus communis choledochus), and the hepatic duct. The cystic duct, typically exhibiting a very small diameter of about 1/8 inch (3.175 mm) joins the hepatic duct to form a common bile duct which extends to an orifice upon the summit the papilla situated at the inner side of the descending portion of the duodenum. The external coat of the cystic duct is fibrous and composed of strong fibro-areolar tissue with a certain amount of muscular tissue arranged in a circular manner around the duct.
Because gall stones may be present in the common bile duct, under earlier, open surgical cholecystectomy procedures, the surgeon has been able to palpate the common bile duct and visualize its diameter for determining whether a cholangiogram would be necessary to detect any occult stones. This procedure was essentially straightforward utilizing the surgeon's stereoscopic direct vision and tactile senses at the fingertips. However, in laparoscopic surgery, the common bile duct is not tactilely accessible by the surgeon, but is viewed two-dimensionally and remotely on a T.V. screen, making it difficult for the surgeon to appreciate turns in the ductal structures. Thus, and as retained stones in the biliary anatomy present the possibility for injuries to the major ductal structures during laparoscopic cholecystectomy, a cholecystcholangiographic protocol is generally indicated for management of ductal stones. Indeed, cholangiography is useful both for demonstrating the cystic duct/common hepatic duct junction to delineate abnormal anatomy, and for indicating the presence of any stones in the common bile duct.
One technique for cholecystcholangiography involves retracting the gallbladder laterally and elevating it up to the abdominal wall. Upon being brought into apposition with the abdominal wall, the gallbladder is then punctured percutaneously with a needle to aspirate bile and to effect a decompression. A syringe of contrast material such as a barium fluid or the like then is attached to the needle for refilling the gallbladder with an amount of the contrast material equal in volume to the amount of bile which was aspirated. At this point, the gallbladder is viewed radiographically with a fluoroscope or the like to assess the biliary anatomy and to determine whether stones are present within the common bile duct.
Although the above-described cholangiographic technique is relatively easily effected given the constraints of two-dimensional remote vision and diminished tactile data, the injection of contrast fluid directly into the sac of the gallbladder sac engenders a risk of flushing any stones contained therein into the ductal system where removal is made more difficult. Accordingly, a cystic duct cholangiography protocol is often specified. In this protocol, the gallbladder is grasped with atraumatic grasping forceps at the fundus and, optionally, at the infundibulum to place the cystic duct in tension. Any adhesions between the gallbladder and the adjacent organs, e.g., omentum, right colon flexure and duodenum, may be bluntly divided or transected with a hooked electrode or scissors. With the gallbladder separated and adequate traction maintained, the cystic duct is dissected from its areolar and/or adipose investment using forceps, hook electrodes, or scissors. In this regard, it is generally preferred that dissection is begun at the infundibulum and proceeds in the direction of the common bile duct to expose junction of the cystic and hepatic ducts.
Upon adequate exposure of the duct, the upper neck of the gallbladder is then closed by peripherally clipping the cystic duct near its junction with the infundibulum of the gallbladder. With the gallbladder grasped near the infundibulum to stretch the cystic duct, an instrument such as a pair of laparoscopic microscissors is used to partially transect the cystic duct on the common bile duct side of the previously placed clip. Following the partial transection of the cystic duct, a cholangiography catheter is percutaneously inserted at an angle to orient the catheter towards the opening in the duct. The catheter is selected as being flexible and having outer diameter suited for insertion into the duct. The tip of the catheter is guided into the cystic duct through the opening, and is secured in the duct by clipping. It generally is preferred that saline is injected through the catheter during clipping to assure its potency. Once the catheter is secured within the cystic duct, cholangiography is performed in a routine fashion.
After satisfactory cholangiograms have been obtained, the cholecystectomy procedure continues with the retrieval of any ductal stones and, thereafter, with the division of the cystic duct. With respect to the division of the cystic duct, the duct first is clipped centrally near its junction with the common bile duct. The duct then is divided between the central clip and the peripheral clip previously placed near the infundibulum of the gallbladder. As the duct is divided, traction is maintained on the neck of the gallbladder away from the liver to more clearly expose the cystic artery.
With the cystic duct divided, the cystic artery next may be addressed. Indeed, it is preferred to first divide the cystic duct before the cystic artery is dissected as closure and division of the cystic duct as a first step permits a better identification and a safer closure of the cystic artery. As with the cystic duct, the cystic artery, for its identification, also may have to be dissected free of an areolar and/or adipose investment, again with the use of forceps, hook electrodes, or scissors. Division of the artery then may proceed via a double clip ligation and a transection with scissors between the clips.
Following the division of the cystic duct and arteries, the intraoperative procedure continues with the dissection of the gallbladder from the liver. Generally, this dissection proceeds by alternately retracting the gallbladder medially and laterally with concurrent elevation to place the interposing tissue under tension. With the interposing tissue placed in tension, it may be separated either bluntly with dissecting forceps, sharply with scissors, or with a monopolar electrosurgical instrument or a bipolar forceps. The gallbladder then may be removed from the body through a lateral trocar. For further information concerning laparoscopy and its use in conjunction with cholecystectomy, reference is made to the following publications, the disclosures of which are expressly incorporated herein by reference:
"Laparoscopy" by J. W. Saleh, W. D. Saunders Co., 1988. PA1 "Laparoscopic Abdominal Surgery" by J. N. Graber, L. S. Schultz, J. J. Pietrafitta, and D. F. Hickok, McGraw-Hill, Inc., 1993. PA1 "Minimally Invasive Surgery" by J. G. Hunter and J. M. Sackier, McGraw Hill, Inc., 1993.
As was mentioned, the above-described cystic duct cholangiography protocol often is specified in cholecystcholangiography to minimize the risk of stone migration from the gallbladder sac into the ductal system. Unfortunately, such protocol necessarily entails the dissection of the cystic artery from its investment prior to the taking of a cholangiogram and the identification of the biliary anatomy. The laparoscopic surgeon must therefore employ what amounts to an exploratory technique in attempting to delineate the cystic duct without causing trauma to the surrounding structures. The exploration is complicated, however, in that the surgeon must operate remotely without direct stereo vision or tactile response.
Indeed, the most common tool for the laparoscopic dissection of the cystic duct and arteries heretofore has been scissors, which are generally used in concert with forceps and retractors to effect the severance or traumatic avulsion of investment tissue. However the two-dimensional field afforded to the surgeon during laparoscopic procedures complicates the use of scissors or forceps. Such complication presents an increased risk that adjacent anatomical structures may be accidentally damaged as a result of the surgeon lacking direct stereoscopic access to the structure being dissected. Moreover, avulsive instruments such as forceps, hemostats, and tweezers inherently cause a certain amount of trauma to surrounding tissue. A not uncommon occurrence is the severance of a hepatic artery branch with the immediate result of abandonment of the laparoscopic procedure and resort to conventional open surgery.
More recently, laparoscopic surgeons have experimented with atraumatic, blunt dissecting instruments such as the Kittner or "peanut" gauze dissector. Such dissectors generally comprise an elongate 5 or 10 mm diameter rod terminating at a blunt spherical or cylindrical tip formed of a wound cotton or other fibrous material. Other of the blunt dissectors terminate in a cylindrical tip comprised of a wound, textured fabric.
Although the use of such blunt dissectors presents a lessened risk of traumatic injury to anatomical structures adjacent to the structure being dissected, the relative smoothness of the fibrous or fabric tip material precludes their use for the abrasive removal of investment tissue. The relatively low coefficient of friction of the fibrous or fabric tip material also makes the known dissectors relatively ineffective for tactilely engaging and circumferentially retaining areolar investment tissue. Thus, the use of the blunt dissectors heretofore known in the art has been limited to the dissection of structures that are loosely attached to and can be easily separated from one another via the insertion of the dissector therebetween. Additionally, the porosity and inherent structural weakness of fibrous or fabric tips necessitates that such instruments be made disposable rather than reusable. Indeed, during surgery, the fibrous or fabric tips may swell or unravel to such an extent that the instrument must be removed from the patient and replaced with a new instrument. Overall, the blunt dissectors heretofore known may be seen as less than optimally efficient and may unacceptably extend the duration of the laparoscopic procedure. It is therefore apparent that the provision of a blunt dissecting instrument which aids the laparoscopic surgeon in delineating, for example, the cystic duct and arteries would be well-received by practitioners and would represent an important improvement in laparoscopic surgery.